Chapter 13: Fluorescent Sensors for Water

The development of optical sensing methods for the detection and quantification of water in solutions, solids, gases, and products or water on materials surfaces has received considerable attention in recent years from the viewpoint of fundamental studies in photochemistry, analytical chemistry, and photophysics and is eagerly anticipated in industry because of their potential applications to environmental and quality control monitoring systems. Therefore, if we can develop organic fluorescent sensors for water, the fluorescence spectroscopic technique utilizing the fluorescent sensors allows the visualization as well as detection and quantification of water content in samples using a highly sensitive and quick flow analysis based on the changes in wavelength, intensity, and lifetime of photoabsorption and photoluminescence depending on the water content. This chapter provides the fluorescence analysis for the detection, quantification, and visualization of water based on PET (photoinduced electron transfer), FRET (Förster resonance energy transfer), ICT (intramolecular charge transfer), AIEE (aggregation-induced emission enhancement), or SFC (solvatofluorochromism) of newly developed colorimetric and fluorescent dyes and their optical sensing mechanism for the detection and quantification of water content in solvents, and polymer films doped with fluorescent sensors for water as one of the most promising and convenient functional materials for visualizing moisture and water droplets.